A screen formed on the inner surface of the panel of a color cathode ray tube has a multi-layered, thin film structure as shown in FIG. 1. This screen comprises a plurality of fluorescent stripes or dots 1 or red, green and blue colors which are alternately arranged on the inside of panel P with black matrix stripes 2. The black matrix stripes isolate the respective neighboring fluorescent stripes of different colors and absorb the light entering from outside the panel. A thin metal film 3, is formed on the outermost surface of the structure.
Both the fluorescent stripes 1 and black matrix stripes 2 are formed substantially on the same plane. The thin metal film 3 covers the fluorescent stripes 1 and black matrix stripes 2. The reference letter "S" in the drawing denotes the skirt of panel.
This final multi-layered structure is only a portion of all of the layers which are formed during manufacture of the screen. The remainder of the materials used during manufacture of the screen are removed by burning and decomposition through the so-called etching process and baking process.
Description of the above process is now given in greater detail. Initially, the whole inner surface of the panel is coated with a precoating agent. This forms an adhesion strengthening layer as the first layer on the panel. Next, a sensitive resin film coating is applied to the adhesion strengthening layer in order to form a black matrix. This sensitive resin film is applied by way of photo lithography and the film is then removed in a developing process, which is the final step of the black matrix stripe manufacturing process.
After the black matrix stripes are formed, different colored fluorescent stripes are formed alternately in the intervals between the respective neighboring black matrix stripes. Following this, the whole surface of the above is covered with filming agent and dried out. This produces a layer of organic film on the black matrix stripes and fluorescent stripes. Finally, a metal film, for example, an aluminum film, is applied to cover the multi-layered structure. The layer of organic film applied to the stripes serves to prevent the metal film from intruding into the fluorescent stripes and to improve upon the flatness of the metal film.
Once formation of the layered structure is complete, the layer of organic film and the lowermost adhesion strengthening layer are removed using a baking process.
In the above screen manufacturing process, it is during the baking process that there is concern that the metal film will become swollen and deformed. This concern is particularly strong for the portion of the metal film which is formed on the panel skirt, the peripheral portion of a screen. The metal film swelling occurs because the precoating agent is rapidly vaporized by high temperature heat, and the gas generated therefrom causes the metal film to become swollen up.
The swollen metal film may peel off into pieces. These pieces of metal film consequently remain as foreign objects inside the cathode ray tube, and may result in arcing between electron guns and the phenomenon of the blocking of holes of the shadow mask.